I’ve always wanted to build a trebuchet. This spring, while playing with the kids, I cobbled one together out of plastic tube, metal chairs, bricks, and duct tape. It would throw a golf ball about ten feet high and two inches forwards.

Two weeks later, while in a hardware store for unrelated reasons, I decided to try again. I pulled out a pocket notebook, and started drawing dimensions and boards, based on the rules of thumb from The Algorithmic Beauty of the Trebuchet.

The kids and I bought the boards, and that night we had a trebuchet about three feet high standing in the living room.

I designed the trebuchet to fire golf balls, but I switched to a much less aerodynamic projectile, a partially filled water bottle, to avoid breaking neighbor’s windows. The real beauty, though, is in launching glowsticks up through the night sky.